Small tin mine, formerly named Wheal Mary, is situated between St. Dennis and Whitemoor. Its historical production records indicate that it yielded 4 tons of black tin in 1874 under the Wheal Mary name and an additional 25 tons of black tin between 1901 and 1905 when it operated under the name St. Dennis Crown Mine. At the site, a small engine house remains standing as a testament to its past operations.